1. Technical Field
The present invention relates generally to computer software and, more particularly to location determination of a mobile client.
2. Description of Related Art
In mobile and portable computing, knowledge of the location of the computer is valuable: it permits customizing the behavior of the computer and its software in many valuable ways. For example, if the computer is equipped with an emergency button (e.g., “call 911”), the behavior of this button can be changed to call the closest emergency service provider. If there is an equipment configuration associated with each location, the behavior of the operating system of the computer can be changed so as only to show the local equipment (e.g., printer, scanner), thus simplifying the presentation and making it less confusing. Certain wide-area networking protocols (e.g., login) can be automated as well.
Many means are possible for determining the current location of the computer. A Global Positioning Satellite (GPS) receiver can determine its location by analysis of radio signals received from satellites. Dead-reckoning means (inertial guidance systems, such as gyroscopes and accelerometers) can give relative position from the last known good waypoint. The computer can even ask the user to select the current location via a graphical dialog. Each of these means has its advantages and drawbacks. GPS location takes power and does not work well in certain locations characterized by many reflected radio signals, or locations within buildings where radio signals from the satellites do not penetrate well. Dead-reckoning systems accumulate error over time until recalibrated at a waypoint. Both GPS and dead-reckoning systems require some weight and space for their implementation, and this may be disadvantageous to equipment portability. The alternative of asking the user to supply the current location may not work because the user may not know the current location, but, more importantly, the computer may not be attended by its user and therefore there will be no operator to have a dialog with.
Therefore, it would be desirable to have method and system for determining the location of a portable or mobile computer that requires less hardware than current systems.